Detailed On-Water Measurements of Blade Forces and Stroke Efficiencies in Sprint Canoe

Measurements of blade forces are made using a load cell mounted between the blade and shaft of a modified paddle. All six force components and moments are measured simultaneously to give a full picture of blade hydrodynamic forces as the centre of pressure on the blade varies throughout the stroke. Blade orientation was also measured using inertial measurement units, one on the blade shaft, and the other on the canoe giving the relative position of blade with respect to the boat, as well as boat speed, acceleration and motion. Testing of the instrumented paddle was undertaken by one of the authors, an ex-national team athlete. The measured forces (and propulsive/vertical forces) are analyzed in detail through the stroke and as stroke averages. Various measures of propulsive efficiency are proposed using either the input force and propulsive force, or using input force and boat speed, and can be used for stroke analysis, or as training tools/targets.